Question 1

Which of the following best describes the null hypothesis ($$H_0) in a $$hypothesis test?

Accepted Answer

It is a statement that the population parameter is equal to a specific value.

Question 2

A pharmaceutical company wants to prove that a new drug is better than the current standard. Which is the most appropriate way to set up the hypotheses?

Accepted Answer

$$H_0$$: New drug is no different from current; $$H_1$$: New drug is better than current.

Question 3

Which of the following is a Type I error in hypothesis testing?

Accepted Answer

Rejecting $$H_0$$ when $$H_0 is $$true.

Question 4

A cereal box is labeled as containing 20 ounces. An inspector suspects the mean weight is less than this. What are the correct null and alternative hypotheses?

Accepted Answer

$$H_0$$: \mu = 20$$; H_1$: \mu \u003c 20$$

Question 5

If the significance level $$\alpha is $$set to 0.01 instead of 0.05, what is the effect on the probability of making a Type I error?

Accepted Answer

The probability of a Type I error decreases.

Question 6

Which formula is used to calculate the test statistic for a sample proportion?

Accepted Answer

$$z = \frac{\hat{p} - p}{\sqrt{pq/n}}$$

Question 7

In the P-value method, what is the correct decision rule for a right-tailed test?

Accepted Answer

Reject $$H_0 if P-$$value $$\u003c \alpha.$$

Question 8

A researcher tests the claim that the mean cholesterol level in a population is different from 200 mg/dL. Which type of test should be used?

Accepted Answer

Two-tailed test

Question 9

Suppose you conduct a hypothesis test and obtain a test statistic $$z = 2.1$$ with a critical value of $$z = 1.96$$ for $$\alpha = 0.05 in a $$right-tailed test. What is the correct conclusion?

Accepted Answer

Reject $$H_0$$ because $$z is $$greater than the critical value.

Question 10

Which statement about the power of a hypothesis test is correct?

Accepted Answer

Power is the probability of rejecting a false null hypothesis.

Question 11

In a hypothesis test, why is it misleading to say we 'accept' the null hypothesis?

Accepted Answer

Because failing to reject $$H_0$$ only means the evidence isn't strong enough to reject it.

Question 12

A sample of 926 internet users shows 52% use two-factor authentication. If the null hypothesis is $$p = 0.5$$, what is the test statistic for this proportion?

Accepted Answer

$$z = \frac{0.52 - 0.5}{\sqrt{(0.5)(0.5)/926}}$$

Question 13

Which of the following best describes the critical region in hypothesis testing?

Accepted Answer

The set of values for the test statistic that lead us to reject $$H_0.$$

Question 14

If a hypothesis test uses the critical value method and the test statistic falls outside the critical region, what is the correct decision?

Accepted Answer

Fail to reject $$H_0.$$

Question 15

Which of the following is true regarding the relationship between Type I and Type II errors?

Accepted Answer

Decreasing the probability of Type I error usually increases the probability of Type II error.

Question 16

A medical researcher wants to test if a new treatment changes the mean recovery time from 10 days. Which is the correct alternative hypothesis?

Accepted Answer

$$H_1$$: \mu 
eq 10$$

Question 17

Which sampling distribution is appropriate for testing a claim about a population mean when the population standard deviation is unknown and $$n \u003e 30$$?

Accepted Answer

t-distribution ($$t)$$

Question 18

In hypothesis testing, what does the P-value represent?

Accepted Answer

The probability of obtaining a test statistic at least as extreme as the observed, assuming $$H_0 is $$true.

8.1

Guida di studio - Domande di pratica

Study guide - Flashcard